Press configure to select the directory the WAVs will go (forgot to mention this one, thanks go to Lumberjack and Reverend Ike for bringing it up )

Load the mp3s you want to convert to wav

Press play and wait

Remember to set output back to waveOut or DirectSound afterwards, for normal playback.

Notes:

The above works for other conversions like VQF to WAV, or even WAV to WAV, with the notable exception of analog CD (not 100% sure) and secure formats (read:WMA)

For WAV to WAV (eg. for converting an 8-bit 22KHz file to CD Quality, make sure you checkmark "Convert to Format" in Diskwriter config, and make sure "PCM 44,100 KHz, 16 Bit, Stereo" is the selected format).

or using the CD Reader plugin (Winamp 2.81 and earlier) as input and DiskWriter as output. You can also use one of PP's plugins, the ACM output plugin instead of nullsoft's. (note, this is now the default Diskwriter with Winamp v2.77)

MP3 to MP3
No, youre not seing double. You might need this to save on disk space, copy file to a floppy or upload music to your portable player. The thing to note here is that even if you increase the bitrate the quality wont rise. So compressing with MP3 (or any other lossy format btw) goes only one way